An image forming apparatus includes a secondary transfer roller in order to bring an image bearing member such as a transfer belt and a recording medium into press-contact with each other and transfer an image onto the recording medium.
When the recording medium is conveyed to the secondary transfer roller at predetermined timing, a toner does not adhere to the secondary transfer roller. However, if the recording medium is not conveyed at the predetermined timing, for example, when a jam of the recording medium occurs, a toner carried on the image bearing member adheres to the secondary transfer roller. In this case, when the next recording medium is conveyed to the secondary transfer roller, the toner adheres to the rear surface of the sheet and pollution occurs.
In order to prevent the pollution, the image forming apparatus has a mechanism that brings a cleaning member into contact with the secondary transfer roller to scrape off the adhering toner. A carrying mechanism carries a waste toner scraped off by the mechanism to a tank for storing the waste toner.
The tank for storing the waste toner needs to have a certain appropriate size. Therefore, a layout of the tank is limited in terms of the size. In other words, a degree of freedom of an arrangement of the tank is limited because of a relation between the tank and other components of the image forming apparatus.
In order to reduce a size of the image forming apparatus under such a limitation, the carrying mechanism that carries the waste toner to the tank is desirably more space-saving. In particular, when an opening of the tank is set higher than a position of the cleaning member, a mechanism that carries the waste toner upward is necessary.
Concerning this point, a carrying mechanism that rotationally moves a belt, which has teeth and is inclined, to thereby carry a waste toner accumulated in the teeth upward is proposed (see, for example, JP-A-2005-49677).
However, this technique has a problem in that it is difficult to use spaces above and below the carrying mechanism because the carrying mechanism tilts and, as a result, desired space-saving cannot be attained.